Turbocharger bearing assembly and method for providing the same

ABSTRACT

An integrated bearing assembly includes a thrust bearing disposed along a face of a turbocharger casing in a turbocharger and extending circumferentially around an axis of rotation of a rotor of the turbocharger, and a dual film journal bearing radially disposed between the rotor and the turbocharger casing which can be semi-floating or fully floating. The journal bearing includes a shoulder step radially extending away from the rotor. The shoulder step of the journal bearing engages one or more of the thrust bearing or the turbocharger casing to prevent axial movement of the dual film journal bearing relative to the turbocharger casing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/336,890, filed on 28. Oct. 2016, which is a continuation-in-part ofU.S. patent application Ser. No. 15/199,442, filed 30 Jun. 2016. Theentire disclosures of these application are incorporated herein byreference.

FIELD

The subject matter described herein relates to hydrodynamic bearingsused in turbochargers.

BACKGROUND

Some turbochargers utilize semi-floating dual film journal bearings totake advantage of the high tolerance of these bearings to the imbalancesin the rotor system. Sometimes, a journal bearing is integrated with athrust bearing for a compact design and to use the same oil feed anddrain passage. These types of bearings may be heavy-duty bearings withthe ability to support axial and/or radial loads of the rotor in theturbochargers.

These types of journal bearings, however, need specific mechanicalboundary conditions to allow the journal bearing to move or float in theradial direction, while being prevented from rotation and alsorestrained in the axial direction. In order to provide such acomplicated mechanical boundary condition, additional parts or fastenersmay need to be added to the turbocharger. These parts are part of thebearing design in the turbocharger to prevent or restrict movement ofthe journal bearings.

For the benefits achieved by adding a semi-floating journal bearing to aturbocharger, adding new parts to the turbocharger also introducesproblems. For example, the new parts add additional points of failure ofthe turbocharger, may require longer time to install on a turbocharger,can increase the cost of the turbocharger, and/or can make it moredifficult or costly to retrofit an existing turbocharger with thesemi-floating journal bearing.

BRIEF DESCRIPTION

In one embodiment, an integrated bearing assembly includes a thrustbearing disposed along a face of a turbocharger casing in a turbochargerand extending circumferentially around an axis of rotation of a rotor ofthe turbocharger, and a dual film journal bearing radially disposedbetween the rotor and the turbocharger casing. The journal bearingincludes a shoulder step radially extending away from the rotor. Theshoulder step of the journal bearing is placed and axially restrainedbetween the casing of the turbocharger and the thrust bearing with aclearance. Therefore, it prevents axial movement of the journal bearingrelative to the thrust bearing or the turbocharger casing.

In one embodiment, an integrated bearing assembly includes a thrustbearing disposed along a face of a turbocharger casing. The thrustbearing includes a recess along an inner diameter of the thrust bearing.The bearing assembly also includes a dual film journal bearing radiallydisposed between a rotor and the turbocharger casing. The journalbearing includes a shoulder step radially extending away from the rotortoward the thrust bearing, and is located in the above mentioned recessof the thrust bearing. The shoulder step of the journal bearing preventsaxial movement of the journal bearing by engaging one or more of thethrust bearing or the turbocharger casing.

In one embodiment, a method includes obtaining a semi-floating journalbearing of a turbocharger having an outwardly and radially extendingshoulder step, positioning the journal bearing into a casing of theturbocharger, and positioning a thrust bearing onto a surface of thecasing of the turbocharger such that the shoulder step of the journalbearing engages one or more of the thrust bearing or the casing of theturbocharger to prevent axial movement of the journal bearing relativeto the one or more of the thrust bearing or the casing of theturbocharger.

BRIEF DESCRIPTION OF THE DRAWINGS

The present inventive subject matter will be better understood fromreading the following description of non-limiting embodiments, withreference to the attached drawings, wherein below:

FIG. 1 illustrates an integrated bearing assembly;

FIG. 2 illustrates the thrust bearing of the integrated bearing assemblyshown in FIG. 1 ;

FIG. 3 illustrates the semi-floating journal bearing of the integratedbearing assembly shown in FIG. 1 ;

FIG. 4 illustrates the spacer ring of the integrated bearing assemblyshown in FIG. 1 ;

FIG. 5 illustrates the turbocharger housing where the semi-floatingjournal bearing assembly shown in FIG. 1 is installed into;

FIG. 6 illustrates a perspective view of a turbocharger bearing assemblyaccording to one embodiment of the inventive subject matter describedherein;

FIG. 7 illustrates another perspective view of the turbocharger bearingassembly shown in FIG. 6 ;

FIG. 8 illustrates a cross-sectional view of the turbocharger bearingassembly shown in FIGS. 6 and 7 ;

FIG. 9 is a cross-sectional view of a turbocharger having the bearingassembly shown in FIGS. 6 through 8 according to one embodiment, asassembled in the turbocharger casing;

FIG. 10 is a cross-sectional view of a turbocharger having anotherembodiment of a bearing assembly, as assembled in the turbochargercasing;

FIG. 11 is a cross-sectional view of a turbocharger having anotherembodiment of a bearing assembly, as assembled in the turbochargercasing; and

FIG. 12 illustrates a flowchart of a method for providing a bearingassembly for a turbocharger.

DETAILED DESCRIPTION

The inventive subject matter described herein provides an integrationscheme for bearing assembly, including a semi-floating journal bearingand a thrust bearing in the turbocharger. This integration designprovides appropriate mechanical boundary conditions for a semi-floatingjournal bearing with a simple design, without adding more components,parts, or fasteners to the turbocharger. As a result, the inventivesubject matter described herein facilitates simple and effectiveintegration of the thrust bearing and semi-floating journal bearing intonew and/or existing (e.g., in-service) turbochargers as a retrofitmodification. The integrated dual film bearing assembly can be easilyand quickly introduced into turbochargers currently in-service, withoutthe need to machine the cast casings of the turbochargers, which can bea significant, time-consuming and expensive process.

FIGS. 1 through 5 illustrate views of a semi-floating journal bearingassembly 100. The bearing assembly 100 shown in FIGS. 1 through 5 doesnot include certain aspects of the inventive subject matter describedherein. The bearing assembly 100 includes a thrust bearing 200 to whichthe semi-floating journal bearing 300 is coupled. A spacer ring 400 iscoupled with the journal bearing 300 such that the journal bearing 300is between the thrust bearing 200 and the spacer ring 400. Retainingtabs 102 are engaged with the spacer ring 400 and bolted to the casingor housing 500 of the turbocharger. The rotor of the turbocharger islocated in an opening 106 of the bearing assembly 100.

The spacer ring 400 keeps the journal bearing 300 axially in place,along an axial direction 104 of the bearing assembly 100. The thrustbearing 200 and journal bearing 300 have mating features (e.g., recesses202 and protrusions 302) that engage each other to prevent rotation ofthe journal bearing 300 around the rotor or opening 106. Thrust bearingitself is in contact with the turbocharger casing 500 and prevented fromrotation using multiple (e.g., four) dowel pins placed in holes 501 inthe casing, as shown in FIG. 5 . These dowel pins engage with multiple(e.g., four) trenches 203 machined on the backside of the thrustbearing, as shown in FIG. 2 . Connecting the spacer ring 400 to thecasing of the turbocharger with the retaining tabs 102 prevents thespacer ring 400 from axially moving relative to the journal bearing 300,which prevents axial movement of the journal bearing 300 (as describedabove).

However, the addition of the spacer ring 400, mating features, andretaining tabs 102 adds significant complexity, cost, and points ofpotential failure to the turbocharger. This can make retrofitting anexisting turbocharger with the bearing assembly 100 too expensive orcomplex to do on a large scale, such as across a fleet of turbochargersdue to manufacturing variances in the turbochargers. As a result, thesetypes of bearing assemblies 100 may not be as widely used as possible.

FIG. 6 illustrates a perspective view of a turbocharger bearing assembly600 according to one embodiment of the inventive subject matterdescribed herein. FIG. 7 illustrates another perspective view of theturbocharger bearing assembly 600 shown in FIG. 6 . FIG. 8 illustrates across-sectional view of the turbocharger bearing assembly 600 shown inFIGS. 6 and 7 . The bearing assembly 600 may be used in a turbochargerin place of the bearing assembly 100 shown in FIGS. 1 through 5 as asubstitution of the integrated bearing system. This two-piece bearingdesign eliminates the need for the spacer ring, retaining tabs and otherfasteners used to bolt the tabs to the casing. The bearing assembly 600includes a thrust bearing 602 coupled with the journal bearing 604. Theaxial direction 608 represents the axis of rotation of the rotor that isdisposed in the opening 606. The thrust bearing 200 is placed between athrust collar which is part of the rotor assembly and the casing of theturbocharger. The thrust bearing 200 carries the axial load from therotor to the casing through lubrication.

FIG. 9 is a cross-sectional view of a turbocharger 900 having thebearing assembly 600 shown in FIGS. 6 through 8 according to oneembodiment. The axis of a turbocharger rotor 912 of the turbocharger 900is designated as 608 in this cross sectional view. Part of theturbocharger casing is shown as 902, which directly engages with thethrust bearing 602 along a face surface 918 of the thrust bearing 602.The casing 902 also engages with the outer diameter of the semi-floatingjournal bearing 604 via a lubricating oil film along an outer surface922 of the journal bearing 604. The semi-floating journal bearing 604engages the shaft of the turbocharger rotor 912 through a lubricatingoil film along an inner surface 924 of the journal bearing 604. Thethrust bearing 602 also engages a thrust face 928 of the rotor 912. Asection 901 of the thrust bearing 602 represents a radially extendinglubricating oil feed groove into the thrust bearing 602. Several ofthese groves are visible in FIG. 7 .

Axial motion of the semi-floating dual film bearing 604 is restrainedusing a small shoulder step 906 in the journal bearing 604. Thisshoulder step 906 fits into a recess 916 extending upward or radiallyoutward into the thrust bearing 602. The shoulder step 906 isconstrained between the turbocharger casing 902 and the thrust bearing602. However, there is enough axial and radial clearance between thethrust bearing 602 and the journal bearing 604 at the points of contactbetween the bearings 602, 604 in the shoulder step 906 to allow thejournal bearing 604 to float, or radially move, relative to the thrustbearing 604 in one or more directions.

The shoulder step 906 may not be symmetrical along or about the entire360 degrees or circumference of the outer surface 922 of the journalbearing 604. The shoulder step 906 can include the flat segment 610(shown in FIG. 8 ) that engages the mating flat segment 612 (shown inFIGS. 6 and 8 ) of the thrust bearing 602, or any other matingdiscontinuity between the thrust and journal bearings 602, 604. Thesemi-floating journal bearing 604 is prevented from rotating relative tothe thrust bearing 602 via the mating feature engagement between theflat segment 610 of the journal bearing 604 and the flat segment 612 ofthe thrust bearing 602.

The bearing assembly 600 shown in FIG. 9 optionally includes one or moredowel pins 908 extending through the thrust bearing 602 and theturbocharger casing 902. These dowel pins 908 adjust the positioning ofthe thrust bearing 602 relative to the casing 902 and prevent the thrustbearing 602 (and therefore the semi-floating journal bearing 604) fromrotation relative to the casing 902. The bearing assembly 600 shown inFIG. 9 optionally includes an oil feed cavity 903 and/or one or more oilfeed passages 910 extending through the journal bearing 604 and thethrust bearing 602. These passages 910 provide a conduit in whichlubricating oil can move to the thrust bearing 602 from the oil supplyprovided to the journal bearing 604.

FIG. 10 is a cross-sectional view of a turbocharger 1000 having anotherembodiment of a bearing assembly 1002. The bearing assembly 1002includes a thrust bearing 1004, which may represent the thrust bearing602 shown in FIGS. 6 through 8 . The bearing assembly 1002 also includesa semi-floating journal bearing 1008, which may represent the journalbearing 604 shown in FIGS. 6 through 8 . This is another embodiment ofthe inventive design which allows simple two-piece integrated bearingdesign. The main difference here from the design proposed in FIG. 9 isthat a shoulder step 1012 in the semi-floating journal bearing 1008 isplaced between the thrust bearing 1004 and a thrust collar, which isconnected to the rotor assembly 912. In this design, the shoulder step1012 is farther from the casing 902 along an axial direction of therotor 912 than the shoulder step 906 shown in FIG. 9 . As a result, atleast part of the thrust bearing 1004 is between the shoulder step 1012of the journal bearing 1008 and the casing 902. The shoulder step 1012is restricted between the thrust bearing 1004 and the thrust collar, andthis prevents axial movement of the journal bearing 1008. In FIG. 9 ,the shoulder step was placed between the casing and the thrust bearing,which has the advantage of allowing the thrust bearing to leverage abigger axial area to carry axial load.

FIG. 11 is a cross-sectional view of a turbocharger 1100 having anotherembodiment of a bearing assembly 1102 installed in the turbochargercasing 1106. The bearing assembly 1102 includes a thrust bearing 1104,which may represent the thrust bearing 602 shown in FIGS. 6 through 8 .The bearing assembly 1102 also includes a semi-floating journal bearing1108, which may represent the journal bearing 604 shown in FIGS. 6through 8 . One difference from the design shown in FIG. 9 is that ashoulder step 1101 in the semi-floating journal bearing 1108 is placedin a recess 1120 in the casing 1106, instead of a recess in the thrustbearing 1104 as shown in FIG. 9 . In this design, the recess 1120 may bemachined or otherwise cut into the casing 1106. Alternatively, therecess 1120 may be formed in the casing 1106 when the casing 1106 iscreated or formed. The shoulder step 1101 of the journal bearing 1108 isaxially restricted between the casing 1106 and the thrust bearing 1104with a clearance. This engagement limits or prevents axial movement ofthe journal bearing 1108. The axial length of a recess 1120 in thejournal bearing 1108 does not carry radial load in this design.

FIG. 12 illustrates a flowchart of a method 1200 for installation of anintegrated semi-floating dual film bearing assembly for a turbocharger.The method 1200 may be used to install one or more of the bearingassemblies described herein and/or for retrofitting an existingturbocharger with one or more of the bearing assemblies describedherein. At 1202, holes are machined in the turbocharger casing and dowelpins are placed in them. These dowel pins will be guides to position thethrust bearing in place and also prevent the rotation of the bearingassembly during operation. These holes may be manufactured in the casingfor new turbochargers or simply be machined through a fixture guide inthe case of a retrofit assembly.

At 1204, the semi-floating journal bearing is positioned in the casingso that the shoulder step in the journal bearing sits against the edgeof the casing. The journal bearing will be fit into the space betweenthe rotor and the casing so that the arm fits into the recess formed inthe casing or thrust bearing, as described above. At 1206, the thrustbearing is positioned on the casing and next to the journal bearing.Positioning of the thrust bearing should be carried out withconsideration of the dowel pins in the casing and mating features in theshoulder step of the journal bearing. At 1208, the turbocharger rotor isplaced into or through the journal bearing and thrust bearing tocomplete the assembly of the integrated bearing assembly between theturbocharger casing and rotor.

In one embodiment, an integrated bearing assembly includes a thrustbearing disposed along a face of a turbocharger casing in a turbochargerand extending circumferentially around an axis of rotation of a rotor ofthe turbocharger, and a dual film journal bearing radially disposedbetween the rotor and the turbocharger casing. The journal bearingincludes a shoulder step radially extending away from the rotor. Theshoulder step of the journal bearing engages one or more of the thrustbearing or the turbocharger casing to prevent axial movement of thejournal bearing relative to the turbocharger casing.

In one example, the thrust bearing includes a recess radially extendinginto the thrust bearing away from the rotor, and wherein the shoulderstep of the journal bearing extends into the recess.

In one example, the recess in the thrust bearing and the shoulder stepin the journal bearing both circumferentially extend around the axis ofrotation of the rotor. The shoulder step in the journal bearing and therecess in the thrust bearing can include flat segments that mate witheach other to prevent rotation of the journal bearing relative to thethrust bearing.

In one example, the shoulder step of the journal bearing radiallyextends away from the rotor and along a surface of the turbochargercasing that also engages the thrust bearing.

In one example, the shoulder step of the journal bearing is spaced apartfrom the turbocharger casing along axial directions that are parallel tothe axis of rotation of the rotor with a portion of the thrust bearingdisposed between the shoulder step of the journal bearing and theturbocharger casing along the axial directions.

In one example, the shoulder step of the journal bearing radiallyextends away from the rotor and into a recess in the turbochargercasing.

In one example, the shoulder step of the journal bearing radiallyextends away from the rotor and along a surface of the thrust bearingthat also engages the turbocharger casing.

In one example, the bearing assembly also includes one or more dowelpins that engage with the thrust bearing and the turbocharger casingalong axial directions that are parallel to the axis of rotation of therotor.

In one example, the one or more dowel pins secure the thrust bearing ina position with respect to the turbocharger casing and restrict rotationof the bearing assembly.

In one embodiment, an integrated bearing assembly includes a thrustbearing disposed along a face of a turbocharger casing. The thrustbearing includes a recess along an inner diameter of the thrust bearing.The bearing assembly also includes a dual film journal bearing radiallydisposed between a rotor and the turbocharger casing. The journalbearing includes a shoulder step radially extending away from the rotortoward the thrust bearing. The shoulder step of the journal bearingprevents axial movement of the journal bearing by engaging one or moreof the thrust bearing or the turbocharger casing.

In one example, the shoulder step of the journal bearing radiallyextends along a surface of the turbocharger casing that also engages thethrust bearing.

In one example, the thrust bearing includes a recess that radiallyextends into the thrust bearing in directions away from the rotor. Theshoulder step of the journal bearing can extend into the recess.

In one example, the shoulder step of the journal bearing is spaced apartfrom the turbocharger casing such that a portion of the thrust bearingis disposed between the shoulder step of the journal bearing and theturbocharger casing.

In one example, the shoulder step of the journal bearing radiallyextends into the turbocharger casing in directions away from the rotor.

In one example, the shoulder step of the journal bearing radiallyextends along a surface of the thrust bearing that also engages theturbocharger casing.

In one example, the turbocharger casing includes a recess radiallyextending into the turbocharger casing. The shoulder step of the journalbearing extends into the recess.

In one embodiment, a method includes obtaining a semi-floating journalbearing of a turbocharger having an outwardly and radially extendingshoulder step, positioning the journal bearing into a casing of theturbocharger, and positioning a thrust bearing onto a surface of thecasing of the turbocharger such that the shoulder step of the journalbearing engages one or more of the thrust bearing or the casing of theturbocharger to prevent axial movement of the journal bearing relativeto the casing of the turbocharger.

In one example, positioning the thrust bearing onto the surface of thecasing of the turbocharger includes positioning the thrust bearing suchthat the shoulder step of the journal bearing extends into a recess ofthe thrust bearing and extends along the surface of the casing of theturbocharger.

In one example, positioning the thrust bearing onto the surface of thecasing of the turbocharger includes positioning the thrust bearing suchthat the shoulder step of the journal bearing extends into a recess ofthe casing of the turbocharger.

In one example, positioning the thrust bearing onto the surface of thecasing of the turbocharger includes positioning the thrust bearing suchthat the shoulder step of the journal bearing is radially spaced apartfrom the casing of the turbocharger.

In one example, the method also includes placing one or more dowel pinsthrough holes in the thrust bearing and the casing of the turbochargerto prevent rotation of the thrust bearing relative to the casing of theturbocharger.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” of the presently describedsubject matter are not intended to be interpreted as excluding theexistence of additional embodiments that also incorporate the recitedfeatures. Moreover, unless explicitly stated to the contrary,embodiments “comprising” or “having” an element or a plurality ofelements having a particular property may include additional suchelements not having that property.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the subject matterset forth herein without departing from its scope. While the dimensionsand types of materials described herein are intended to define theparameters of the disclosed subject matter, they are by no meanslimiting and are exemplary embodiments. Many other embodiments will beapparent to those of skill in the art upon reviewing the abovedescription. The scope of the subject matter described herein should,therefore, be determined with reference to the appended claims, alongwith the full scope of equivalents to which such claims are entitled. Inthe appended claims, the terms “including” and “in which” are used asthe plain-English equivalents of the respective terms “comprising” and“wherein.” Moreover, in the following claims, the terms “first,”“second,” and “third,” etc. are used merely as labels, and are notintended to impose numerical requirements on their objects. Further, thelimitations of the following claims are not written inmeans-plus-function format and are not intended to be interpreted basedon 35 U.S.C. § 112(f), unless and until such claim limitations expresslyuse the phrase “means for” followed by a statement of function void offurther structure.

This written description uses examples to disclose several embodimentsof the subject matter set forth herein, including the best mode, andalso to enable a person of ordinary skill in the art to practice theembodiments of disclosed subject matter, including making and using thedevices or systems and performing the methods. The patentable scope ofthe subject matter described herein is defined by the claims, and mayinclude other examples that occur to those of ordinary skill in the art.Such other examples are intended to be within the scope of the claims ifthey have structural elements that do not differ from the literallanguage of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims.

What is claimed is:
 1. An integrated bearing assembly comprising: athrust bearing disposed along a first surface of a turbocharger casingin a turbocharger and extending circumferentially around an axis ofrotation of a rotor of the turbocharger; and a dual film journal bearingradially disposed between the rotor and the turbocharger casing, whereinan outer surface of the dual film journal bearing is disposed along asecond surface of the turbocharger casing and along a surface of a firstportion of the thrust bearing, wherein the dual film journal bearingincludes a shoulder step radially extending away from the rotor and theouter surface of the dual film journal bearing, the shoulder step of thedual film journal bearing configured to restrict axial movement of thedual film journal bearing relative to the turbocharger casing, whereinthe shoulder step of the dual film journal bearing is spaced apart fromthe turbocharger casing along an axial direction that is parallel to theaxis of rotation of the rotor with the first portion of the thrustbearing disposed between the shoulder step of the dual film journalbearing and the turbocharger casing along the axial direction whereinthe thrust bearing includes a recess radially extending into the thrustbearing away from the rotor, and wherein the shoulder step of the dualfilm journal bearing extends into the recess.
 2. The integrated bearingassembly of claim 1, wherein the recess of the thrust bearing and theshoulder step of the dual film journal bearing both circumferentiallyextend around the axis of rotation of the rotor, wherein the shoulderstep of the dual film journal bearing and the recess of the thrustbearing include flat segments that mate with each other to preventrotation of the dual film journal bearing relative to the thrustbearing.
 3. The integrated bearing assembly of claim 1, furthercomprising one or more dowel pins that engage with the thrust bearingand the turbocharger casing along the axial direction that is parallelto the axis of rotation of the rotor.
 4. The integrated bearing assemblyof claim 1, further comprising one or more dowel pins securing thethrust bearing in a position with respect to the turbocharger casing andrestricting rotation of the bearing assembly.
 5. The integrated bearingassembly of claim 1, wherein a portion of the dual film journal bearingis radially separated from the turbocharger casing by an oil feedcavity.
 6. The integrated bearing assembly of claim 1, wherein thethrust bearing includes a radially extending oil feed groove, and theshoulder step of the dual film journal bearing is axially aligned withthe oil feed groove of the thrust bearing.
 7. The integrated bearingassembly of claim 1, wherein the first portion of the thrust bearing isaxially disposed between the shoulder step of the dual film journalbearing and the turbocharger casing, and a second portion of the thrustbearing is axially disposed between a thrust face of the rotor and theturbocharger casing.
 8. The integrated bearing assembly of claim 1,wherein the shoulder step of the dual film journal bearing is disposedbetween the first portion of the thrust bearing and a thrust face of therotor.
 9. The integrated bearing assembly of claim 1, wherein thesurface of the first portion of the thrust bearing is radially alignedwith the second surface of a turbocharging casing.
 10. An integratedbearing assembly comprising: a thrust bearing disposed along a firstsurface of a turbocharger casing, the thrust bearing including a recessalong an inner diameter of the thrust bearing; and a dual film journalbearing radially disposed between a rotor and the turbocharger casing,wherein an outer surface of the dual film journal bearing is disposedalong a second surface of the turbocharger casing and along a surface ofa first portion of the thrust bearing, wherein the dual film journalbearing includes a shoulder step radially extending away from the rotortoward the thrust bearing, wherein the shoulder step of the dual filmjournal bearing is configured to restrict axial movement of the dualfilm journal bearing relative to the turbocharger casing, wherein theshoulder step of the dual film journal bearing is spaced apart from theturbocharger casing along an axial direction that is parallel to an axisof rotation of the rotor, wherein a portion of the dual film journalbearing is radially separated from the turbocharger casing by an oilfeed cavity.
 11. The integrated bearing assembly of claim 10, whereinthe recess extends radially into the thrust bearing away from the rotor,and wherein the shoulder step of the dual film journal bearing extendsinto the recess.
 12. The integrated bearing assembly of claim 10,wherein the thrust bearing includes a radially extending oil feedgroove, and the shoulder step of the dual film journal bearing isaxially aligned with the oil feed groove of the thrust bearing.
 13. Theintegrated bearing assembly of claim 10, wherein the first portion ofthe thrust bearing is axially disposed between the shoulder step of thedual film journal bearing and the turbocharger casing, and a secondportion of the thrust bearing is axially disposed between a thrust faceof the rotor and the turbocharger casing.
 14. The integrated bearingassembly of claim 10, wherein the shoulder step of the dual film journalbearing is disposed between the first portion of the thrust bearing anda thrust face of the rotor.
 15. The integrated bearing assembly of claim10, wherein the surface of the first portion of the thrust bearing isradially aligned with the second surface of a turbocharging casing. 16.A method comprising: obtaining a journal bearing of a turbochargerhaving an outwardly and radially extending shoulder step; positioningthe journal bearing into a casing of the turbocharger; positioning athrust bearing onto a first surface of the casing of the turbochargersuch that the shoulder step of the journal bearing engages the thrustbearing to restrict axial movement of the journal bearing relative tothe thrust bearing and the casing of the turbocharger, wherein an outersurface of the journal bearing is disposed along a second surface of thecasing of the turbocharger and along a surface of a first portion of thethrust bearing, wherein the first portion of the thrust bearing isaxially disposed between the shoulder step of the journal bearing andthe casing of the turbocharger, and a second portion of the thrustbearing is axially disposed between a thrust face of a rotor and thecasing of the turbocharger; placing one or more dowel pins through holesin the thrust bearing and the casing of the turbocharger to preventrotation of the thrust bearing relative to the casing of theturbocharger; and the positioning the thrust bearing onto the firstsurface of the casing of the turbocharger includes positioning thethrust bearing such that the shoulder step of the journal bearingextends into a recess of the thrust bearing.
 17. The method of claim 16,wherein the positioning the thrust bearing onto the first surface of thecasing of the turbocharger includes positioning the thrust bearing suchthat the shoulder step of the journal bearing is separated from theturbocharger casing by an oil feed cavity.
 18. The method of claim 16,wherein the positioning the thrust bearing onto the first surface of thecasing of the turbocharger includes positioning the thrust bearing suchthat the shoulder step of the journal bearing is axially spaced apartfrom the casing of the turbocharger.